🚀 go-pugleaf

Jerry Bryan <BRYAN@wvnvm.wvnet.edu> writes:

>The old Waterloo WATBOL compiler used invalid opcodes on purpose (trapping
>them with SPIE macro) to effect paragraph tracing.  One of the opcodes
>they chose invoked the APL microcode assist on a 370/148 rather than
>generating on operation exception.  We therefore
>found the problem of why tracing wouldn't work by reading the 148's
>microcode.

If the compiler is generating the code, why can't it simply generate a
branch to a trace subroutine.

When I need tracing, I use a set of trace macros I write.  Works great and
does not affect any registers.  The only requirement is that there be a
base register in effect.
--
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/ Phil Howard -- KA9WGN -- phil@ux1.cso.uiuc.edu   |  Guns don't aim guns at  \
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